RIBLL II, the second Radioactive Ion Beam Line at Lanzhou, is one of the parts of the beam

　　transport line between CSRm and CSRe. It is designed to operate at a higher energy

　　with the maximum magnetic rigidity of 10.64 Tm. The separator of RIBLL II, which consists of two dipoles and ten quadruples, is a mirror-symmetric system, achieving a point-point and parallel-parallel image at its intermediate focal plane with maximum position dispersion. The double achromatism of D = D' = 0 is automatically realized at the final focal plane. Its esolving power of magnetic rigidity is 1200 at the momentum deviation of ΔP/P = ±1% and the divergence of ±25 mrad.

　　The following part is almost a copy of the separator to further purify RIB. The total length

　　of RIBLL II is about 55m. And its ion optics is optimized to a third order in order to obtain high realistic resolving power and to minimize the emittance growth.